如下图:
图1
实现的代码如下:
浏览器:<select id=UserAgent style=width: 320px;/><option value =10>MSIE: Mozilla/4.0 (compatible; Windows …</option><option value =11>Firefox: Mozilla/5.0 (Windows; U; Windows …</option><option value =12>Opera: Opera/9.27 (Windows NT 5.2; U; …</option><option value =